Yes, silicone reduces drag. For example you can spray it on the dashboard of a car, and it gets extra shiny and slippery.
The bad thing is that the rubber sucks it up and gets soft and swollen. It is a good thing for gas sealants in gas mags. If you have a leaking magazine, and don't have a new o ring, just spray silicone in a small tray, put the o ring in it for overnight, and it get softer and a bit bigger - the perfect thing for a good seal.
But for a hopup rubber that's bad.
For any other parts in an AEG it's way too light. It just splashes everywhere from the moving parts just after a few seconds of shooting and nothing is left on the gears.
It's also not good for lubricating gas guns, because it attracts dust and dirt. After a while it will become something like mud. You shoud use dry silicone or teflon spray, or something similar there.
You can use silicone in the barrel, but you have to be careful to avoid the hopup rubber, and it is not for cleaning so it won't do a perfect job. Rubbing alcohol does it better. You can lubricate the barrel after cleaning it with silicone but it doesn't really do any difference.
As for my background: I was working as an airsoft mechanic for some years as a part time job.